The new offering will be available some time in the first half of 2014, and will use AT&T's cloud integration technology, AT&T NetBond, to connect AT&T's Multi-Protocol Label Switching (MPLS)-based VPN offering to Azure. AT&T customers already can use NetBond to connect their own datacenters to AT&T's other cloud offerings.

"Customers of the (new Microsoft-AT&T) solution are expected to benefit from the enterprise-grade security of virtual private networking, with as much as 50 percent lower latency than the public Internet, and access to cloud resources from any site using almost any wired or wireless device," according to Microsoft's press release outlining the new partnership.

Microsoft is looking at the new partnership as a way to try to get more businesses to adopt cloud computing, anticipating that VPN-to-Azure connectivity could lessen security and reliability concerns by companies shy of using the public Internet to access cloud offerings like Azure.

In April, Microsoft made available commercially its own Windows Azure Virtual Networks (codenamed "Brooklyn") technology. Azure Virtual Networks allows users to create private, isolated networks in Azure and treat them as extensions their own on-premises datacenters. With Azure Virtual Networks, users also can set up VPN connections between individual computers and the Azure virtual network without a dedicated VPN device by using the built-in Windows VPN client to tunnel into their Virtual Networks in Azure using the Secure Sockets Tunneling Protocol (SSTP).

I've asked Microsoft whether there's any connection between Azure Virtual Networks and the forthcoming Microsoft-AT&T offering. No word back so far.

Update: A Microsoft spokesperson said that the coming Microsoft-AT&T offering is not related to Azure Virtual Networks. "Today’s announcement is part of Microsoft’s investment in offering multiple seamless ways of extending customers’ on premises network to Windows Azure. Windows Azure Virtual Network relies on an IPsec tunnel over the public internet whereas the solution that we're announcing today will allow customers to integrate their on-premises environment and Azure services via their MPLS based VPNs," said the spokesperson via an emailed statement.